This weekend, some 300,000 fans are expected to descend upon the Town of Speedway to watch the 102nd running of the Indianapolis 500. The Speedway area has been home to the “Greatest Spectacle in Racing” since 1911. The race attracted drivers and fans from all over the world. It has only been cancelled on two occasions: during World War I (1917-1918) and World War II (1942-1945). While there was no roar of race cars, the area was by no means quiet. Instead, the Speedway area became a hub for wartime production, with aircraft engines taking center stage.

Entrepreneur and Indianapolis Motor Speedway co-founder James Allison quite literally shifted gears when he devoted his precision machine shop’s resources on Main Street, just south of the track, to the war effort in 1917. Allison originally built the shop to redesign and rebuild foreign and domestic racecars. By mid-1918, the War Department awarded government contracts to Allison Experimental Company to build parts for the Liberty aircraft engine. According to the National Museum of the United States Air Force, the Liberty represented “America’s major technological contribution to World War I.” The United States’ auto industry produced over 20,000 of these engines during the war and Allison’s Speedway company played its part in this endeavor. The Speedway area also saw the development of an aviation repair depot where workers helped repair, modify, and test hundreds of airplanes and aircraft engines.

Allison Engineering Company Main Street Building and Employees, 1921, photo courtesy of Indiana Memory.

Just one month after the war’s end, in December 1918, the owners of the Indianapolis Motor Speedway announced that the Indianapolis 500 would resume in May 1919. The focus in the Speedway area quickly shifted back to automobiles and racing, but interest in aviation there had just begun. During the 1920s, Allison Experimental Company (Allison Engineering Company by 1921) worked on rebuilding and inverting Liberty engines.

Following James Allison’s death in 1928, General Motors Corp. filed an appropriation request to buy the company the following year. According to the request, General Motors planned to continue Allison’s work in the aviation industry. The Indianapolis Chamber of Commerce promoted the acquisition, stating that with General Motors’ purchase of the company:

Development of this city as a center for the nation’s aviation industry seems assured.

The Chamber of Commerce was not far off the mark. During the 1930s, Allison Engineering Co. focused its efforts on developing a 1,000 horsepower liquid-cooled aircraft engine in the Speedway area. Known as the V-1710, it would become the primary engine that powered Allied fighter aircraft during World War II. Norman Gilman, chief engineer and general manager for the company, reasoned that a liquid-cooled engine could be placed inside the fuselage, where a radial type engine could not and therefore developed high wind resistance or drag, particularly at higher speeds. Despite initial hesitation from both the U.S. Navy and U.S. Army, the Navy placed an order with Allison Engineering Co. for a liquid-cooled airplane engine of 750 horsepower in June 1930. The company designed, built, and delivered this engine to the Navy in March 1932. After completing a 50-hour development test, the Navy accepted the engine in September of that year. The Army Air Corps followed suit and soon after placed an order for the engine with the company.

Throughout the mid-1930s, Allison Engineering Co. worked to improve the engine, with the goal of making it 1,000 horsepower. After several tests and improvements to the design, the company delivered the engine to the Army Air Corps at Wright Field in Dayton, Ohio in March 1937. One month later, the V-1710 passed the 150-hour acceptance test.

By 1939, as war clouds gathered over Europe, Allison Engineering (renamed Allison Division of General Motors in January 1941) committed itself to mass production of the V-1710 aircraft engine in Speedway. At the time, Allison employed 600 people, but this number grew exponentially as orders for the V-1710 came pouring in. In April 1939, newspapers reported that the company would soon triple its facilities with construction of a new plant that would span 200,000 sq. ft. By the end of the year, employment figures had almost doubled to 1,200. Allison Division constructed additional plants in Speedway and the Indianapolis area throughout the war years and with these plants came thousands of additional employees.

Demand for the V-1710 engine made Allison Division one of the three principal manufacturers of aircraft engines in the country during the war, alongside Pratt & Whitney and Wright Aeronautical. In January 1941, Life magazine ran a feature on the engine, highlighting it as the “plane motor on which the Army puts its biggest bet.” By July 1941, the War Department awarded Allison a new contract for the engines. With this contract, total orders for Allison engines since the beginning of the defense emergency program totaled approximately $242,000,000.

America has bet heavily on the Allison engine in its aircraft defense plans, just as the war industries board in 1917 bet everything on the Liberty engine . . . the Allison engine has been delivering regularly for the R.A.F. [Royal Air Force]. Allison is now producing 400 aviation engines a month, where a year ago it was delivering only 150, and expects to approach 1,000 engines a month by the end of 1941. – “More Air Power,” Mason City [Iowa] Globe Gazette, August 13, 1941, 4.

Curtiss P-40, photo courtesy AllisoNews, July 18, 1941, 4.,

Orders and output for the V-1710 engine continued to grow, particularly after the Japanese attack on Pearl Harbor in December 1941. By this point, employment at Allison Division surpassed 12,000. It swelled to 23,019 in October 1943. The company’s growth impacted the Town of Speedway as well. As early as 1940, Indianapolis newspapers commented on Speedway’s growing pains, reporting that officials from the town were seeking state aid to address problems that had come about from the influx of workers to the plants. These problems included the need to improve streets, sanitary conditions, and the need for a better water system. The Indianapolis Times noted that with more employees at the Allison plants came “more money, more home buying, more eating, etc.” School enrollment in the area doubled, church attendance rose greatly, and many new homes were built.

Bell Airacobra P-39, photo courtesy AllisoNews, August 1, 1941, 6.

Meanwhile, Allison Division continued to impress. By March 1944, it built and delivered its 50,000th liquid-cooled engine. By the war’s end, the total figure reached 70,000. These engines powered many of the United States’ fighter planes during the war, including the P-38 Lightning, the P-39 Airacobra, and the P-40 Warhawk. The engine was also used in several fighter planes flown by the Royal Air Force of the United Kingdom.

Lockheed P-38, photo courtesy AllisoNews, August 15, 1941, 4.Program for the Presentation of the Army-Navy Production Award to Allison Division, General Motors Corporation, November 5, 1942.

Allison Division received high praise for the fine precision, workmanship, and durability of the V-1710. It won the Army-Navy “E” Award for excellence in production four times during the war: in October 1942, March 1944, October 1944, and June 1945. By the spring of 1945, Allison Division reduced production schedules of the V-1710 to focus more of its time on building jet engines, which could power planes at much higher speeds. The U.S Army Air Forces had awarded Allison a contract for the production of jet propulsion units in the fall of 1944. The Navy followed the Army’s lead and placed their own order with Allison in the summer of 1945, citing Allison’s “well established reputation for delivering the goods on time.” This reputation would continue through the end of the war in August 1945 and through the post-war years.

As had happened following the conclusion of World War I, racing returned to the Speedway area in 1946 to much fanfare. Left abandoned for nearly five years, the Indianapolis Motor Speedway had fallen into disrepair during World War II. Tony Hulman purchased the track in November 1945 and worked to restore it in preparation for the May 1946 500-mile race. Fans came in droves to witness the 30th running of the Indianapolis 500 that year, as racing returned to center stage in the Speedway area.

Allison’s work in Speedway and its commitment to technological advancements did not end with World War II, but rather continues through today. In addition to continuing its investment and development in the aviation industry following the war, Allison also organized a new department for the design and development of transmissions. The transmissions were manufactured for commercial and military use, with many powering tanks during the Korean War. Their production ushered in a new chapter in the company’s history. Today, James Allison’s experimental company in Speedway , now known around the globe as Allison Transmission, is one of the world’s largest manufacturers of fully automatic transmissions.

Speedway’s aviation repair depot was bordered by Main St. on the west, 14th St. on the north, Polco St. on the east, and roughly contemporary Ford St. and 10th St. on the south. Photo courtesy of William Menkel, “‘New Plans for Old’: The Work of the Aviation Repair Depots,” Aerial Age Weekly, September 1, 1919, 1129, accessed Google Books.

May is finally here and with it racing fans from around the world will soon begin flocking to the Indianapolis Motor Speedway to attend practices and qualifying races in preparation for the Indianapolis 500. For the past century, the Speedway ─ both the track and the adjacent areas of the town ─ have become synonymous with motorsports and racing.

In addition to racing though, the area holds another important place in Indiana and U.S. history ─ as an innovative aviation hub during both world wars. During World War I, the track was used as a landing and flight test field and hangars built on site helped house aircraft. Just south of the track, the Allison Experimental Company manufactured parts for the Liberty Engine, arguably one of America’s greatest contributions to the war. And at Speedway’s aviation repair depot, workers restored 313 planes, 350 engines, and numerous aircraft parts. Their work helped keep our nation’s pilots in the air and made the Speedway area a center for military aviation during the war.

The United States lagged far behind the British, French, and Germans in military aviation when it entered World War I in April 1917. Those countries had been fighting for three years and in that time had understood and capitalized on the value of military aircraft for combat and reconnaissance. American entry in the war spurred rapid expansion of the industry in the country. Although time constraints forced the U.S. to purchase much of its military aircraft from the British and French during this period, the country made great strides in preparing pilots for air service abroad and in the production and repair of engines and training aircraft.

Indianapolis’ central location made it a prime site for aviation repairs and flight testing. Nearby flying fields included Chanute Field in Rantoul, Illinois and Scott Field in Belleville, Illinois, McCook Field and Wilbur Wright Field in Dayton, Ohio, and Selfridge Field in Mt. Clemens, Michigan, among others. Additionally, the proximity of railroad lines in the city and automobile centers in Ohio, Michigan, and Illinois made it easier to access raw materials such as steel, aluminum, and lumber, as well as supplies and spare parts used in repairing wrecked aircraft. Perhaps even more importantly though was the leadership of men like Carl Fisher and James Allison, co-founders of the Speedway, who dedicated their manufacturing resources in the area and the Indianapolis Motor Speedway to the war effort.

Airplanes waiting to be placed in “roundhouse” at Speedway. “Aviation Repair Depot at Speedway City May Become Permanent When Aerial Mail Service is Extended to Midwestern Country,” Indianapolis News, August 10, 1918, accessed Newspapers.com.

The U.S. Army established the aviation repair depot in Speedway on February 4, 1918 with the arrival of the 810th Aero Squadron from Kelly Field in San Antonio, Texas. According to William Menkel, former captain in the U.S. Air Service and commanding officer of the depot, it was the first of the repair depots to get under way and begin repairs in the U.S. Other repair depots later opened in Dallas, Texas and in Montgomery, Alabama. In addition to the 810th Aero Squadron, the Speedway depot was also home to the 809th, 811th, and 821st squadrons. 150 men served in each squadron.

In October 1918, the Speedway Dope, the newsletter of the aviation repair depot, reported that “the commissioned and enlisted personnel [at the depot] constitutes a cosmopolitan community. Mechanicians, [sic] clerks, cooks, and chauffeurs have come from all parts of the Union, and at the Speedway there is no East or West or North or South.” The majority of the civilian mechanics at the repair depot had little knowledge of aircraft before American entry in the war, but within a short time they became experts in the industry and in repair work. The U.S. Air Service established training schools for these men across the country and provided classes in engine assembly and wing and fuselage construction, while also teaching skills such as making and fastening metal parts to the aircraft, sewing fabric on wings, and applying dope varnish to the aircraft. The first wrecked aircraft arrived in April 1918.

Small Parts and Welding Department at the aviation repair depot. Photo courtesy of William Menkel, “‘New Plans for Old’: The Work of the Aviation Repair Depots,” Aerial Age Weekly, September 1, 1919, 1129, accessed Google Books.

Damaged planes were unloaded and often sent to the Dismantling Department where the engine, landing gear, tail surfaces, and other parts were removed, cleaned, and worked on separately before reassembly began. While some of the planes that arrived only needed minor repairs before being shipped back out, others were total wrecks that needed to be completely rebuilt and tested.

By July, output reached three completed planes a day. Perhaps even more impressive though were the modifications made to the aircraft to help increase pilot safety. Workers at the repair depot analyzed incoming wrecks in order to find patterns in destruction. They then used this information to make improvements in design of the aircraft. For example, in his 1919 report on repair depots, Captain Menkel noted that many damaged planes that arrived in Speedway had smashed instrument boards. The instrument board was located so close to the pilot that in the case of a crash their head was likely to hit it. Workers at the depot moved the instrument boards farther away from the pilot’s seat during their repairs. This extra space reduced the chance that the pilot would hit it in a crash, thereby improving the pilot’s safety and lowering the chance of damage to the instrument board.

Propeller Room. Photo courtesy of William Menkel, “‘New Plans for Old’: The Work of the Aviation Repair Depots,” Aerial Age Weekly, September 1, 1919, 1129, accessed Google Books.

The information learned from wrecked aircraft that arrived at the depot also resulted in other modifications, including the reinforcement of longerons and other parts of the plane to lower the chances of damage or fatal injury of the pilot and cutting out sections of the cowl frame to provide more distance between it and the pilot.

In a post report to Washington in January 1919, the Speedway Dope reported 313 airplanes repaired at the depot during 1918, representing a total value of $1,195,550.00 and 350 airplane motors valued at $638,699.00. In addition to these figures, the report noted repairs of wings, ailerons, elevators, rudders, and other miscellaneous parts valued at approximately $300,000.00. Added together, repairs at the depot well exceeded $2,000,000.00. Beyond the economic benefits and savings to the government was the fact that those working at the repair depot helped keep pilots in the air, reducing their chance of injury or death and ultimately giving the U.S. a better opportunity to win the war.

Articles in the Speedway Dope reiterated these sentiments, noting that those who trained or repaired airplanes in the Speedway area might be inclined to downplay the role they played in the war because they were not in the trenches abroad or flying in France. The repair and reconstruction of airplanes was a vital part of the war effort though.

Speedway Dope newsletter letterhead.

The third side of aviation has not only been neglected, but the public generally does not know that it even exists. The repair and reconstruction of damaged planes and motors, constitutes a bit part of the game of aviation. It is that part of the game that must be done and done right, or the other parts would fail to accomplish anything. True it does not carry any of the romance or glamour that follows the course of the pilot and his plane, and neither does it require the enormous financial outlay that goes with production . . . Yet this third side of aviation has been well taken care of and thousands of men who enlisted for service in France have remained at home repair depots and made it possible for others to enjoy foreign service and win international fame.

“The Third Side of Aviation-Rebuilding,” Speedway Dope, November 30, 1918, 1, accessed Indiana State Library Collections.

In the days immediately following the armistice on November 11, 1918, the Speedway Dope wrote that even though the war had ended, production at the depot should continue, as there was still plenty of work to do before completion of the final peace terms. Major Guy L. Gearhart, former commanding officer of the depot agreed. Maj. Gearhart recognized the important role the airplane would play in transportation after the war and believed the repair depot would become a permanent fixture in the Speedway.

The depot’s future remained unclear though. With the war over, immediate aviation interests in the area took a backseat to racing and motorsports. The Indianapolis 500, which had been cancelled in 1917 and 1918, recommenced in May 1919. The resumption of the annual race led to questions and concerns about the track and infield being used for aircraft. Despite initial orders calling for the closing of the depot in March 1919 though, the South Bend News-Times reported that recruitment for men for the U.S. Air Service at the Speedway aviation repair depot continued as of July. By the following year, however, the status of the aviation repair depot was again called into question. Some speculated that it would be removed from the Speedway area and relocated to Fairfield, Ohio. The government officially ordered the abandonment of the repair depot in September 1920 and publicized the sale of buildings and utilities in November of that year.

Although work in the Speedway area shifted back to racing and motorsports, aviation interests did not disappear completely. The Allison Experimental Company (Allison Engineering Company by 1921), located just west of the repair depot, continued to work to improve the Liberty aircraft engine into the 1920s. When General Motors purchased the company in 1929, it expressed a commitment to expanding its work in the aviation field. It was this commitment that made the Speedway area an aviation hub once again during World War II.

Be sure to check back in a few weeks when we examine the vital role the Speedway area played in military aviation in World War II!

Sources Used and Research Note:

William Menkel, “‘New Plans for Old’: The Work of the Aviation Repair Depots,” Aerial Age Weekly, September 1, 1919, 1129-1133, 1144, accessed Google Books.

Much of the information about the aviation repair depot came from articles in the Speedway Dope. The publication ran from September 28, 1918 until February 1, 1919. Copies of the paper can be located at the Indiana State Library.

The Indiana Historical Bureau installed a new state historical marker commemorating the aviation repair depot in Speedway on April 24, 2018. Marker sponsors included Rolls-Royce North America, Rolls-Royce Heritage Trust – Allison Branch, and the Town of Speedway. For more information on the aviation repair depot and additional sources, see: https://www.in.gov/history/markers/4406.htm